Biomass,caloric value and standing crop energy of nine energy willow clones.

We studied the biomass, ash content, caloric value, and standing crop energy of seven exotic energy willow clones (AS625 and AS287 of Salix eriocephala, AAUSC and AAUSL of S. matsudanaS. alba, AFC190 and AFC189 of S.purpurea, ASV1 of S. dasyclados) and two native willow species of S. matsudana and S. integra by methods of direct harvesting, fast ashing and caloric value measurment in Qianan County in Jilin Province, northeast China. The results showed that biomass of AAUSC was the highest (92.9 t/ha), followed by that of AAUSL (65.13 t/ha), and that of AS287 was the lowest one (4.3 t/ha). Ash contents of different organs were 8.28%-12.70% for leaves, 1.98%-4.17% for twigs, and 2.51%-3.82% for stems. Ash-free caloric values were 15 636.29-18 840.77, 18 162.30-19 124.39, and 17 219.71-18 756.31 J/g for leaves, twigs, and stems, respectively. Ash contents and ash-free caloric values differed significantly (P0.01). The standing crop energy of AAUSC was the highest among the seven exotic energy willow clones, that of AAUSL followed, and that of AS287 was the lowest. The standing crop energy of arbor willows were higher than that of shrub willows, and that of exotic willows clones were higher than that of native willows species.